1. Field of the Invention
This invention relates to a mechanism which has a speed reducing function and a function as a clutch when power is transmitted, and more particularly to a speed reduction clutch mechanism which is particularly useful for a driving system of a robot of the direct teaching type.
2. Prior Art
In directly teaching a robot which employs a reduction gear of a high reduction ratio, an output shaft of a servo motor serving as a driving source is rotated by way of a reduction gear. Accordingly, the operating force required when an operator operates an arm of the robot is very large.
Thus, a conventional driving system of a robot of the direct teaching type employs such a construction as, for example, shown in FIG. 6.
In particular, referring to FIG. 6, a servo motor 3 has an output shaft on which a detector 2 for controlling rotation of the motor 3 is mounted. The output shaft of the servo motor 3 is connected to an input shaft of a reduction gear 4 which in turn has an output power shaft connected to a driving force transmitting mechanism of an arm 1 by way of a clutch 5. Further, a detector 6 for exclusive use for teaching of the robot is directly connected to the driving force transmitting mechanism of the arm 1.
Accordingly, upon direct teaching of the robot, the arm 1 and the reduction gear 4 are disconnected from each other by the clutch 5 so that the load of the arm 1 may be reduced. Thus, a teaching position of the arm 1 reached by operation of the arm 1 by an operator is converted into position information by the detector 6 and transmitted to a controlling device (not shown).
On the other had, upon playback of the robot, the arm 1 and the reduction gear 4 are connected to each other by the clutch 5. Consequently, the arm 1 is driven at a predetermined reduction ratio with a predetermined driving torque under the control of the above-mentioned control device.
However, in the driving system of the construction described above, two detectors are necessitated, i.e., one for controlling of the rotation of the motor and the other for teaching of the robot. Accordingly, there is a problem that the driving system is complicated in structure and high in cost.